Fluid pressure governor



Oct. l5, 1935. B. H. THOMPSON 2,017,674

` FLID` PRESSURE GOVERNOR Filed Aug. 15, 1930 I ap 0' /2 2 2a @um Ja /J 2f 7 23 A, a l 28 uunml 1 '1g web l INVENTOR.

BENJAMIN l-I. THOMPSON A TTORNE Y.

Patented Oct. 15, `1935 UNITED STATES PATENT OFFICE FLUID PRESSURE GOVERNOR Application August 13, 1930, Serial No. 475,074

13 Claims.

This invention relates to control devices and more particularly to adevice operated by fluid pressure for controllingthe movement of a valve, a switch or the like.

One object of vmy invention is to provide a iiuid operated control device for eiecting sudden or snap movement of a valve, a switch or the like from one position to another position according to the pressure of fluid acting on said device.

Another object of my invention is to provide a device of the above character which is simple in construction, which has few operating parts and which is adjustable so as to be operated by various pressures.

Other objects and advantages will appear in the following more detailed description of my invention.

In the accompanying drawing; Fig. 1 is an assembly view, mainly in section, of my improved control device incorporated in a fluid compressor control system; Fig. 2 is an assembly View, mainly in section, of a portion of my improved control device taken at right angles to the section shown in Fig. l; and Fig. 3 is a section of the control device taken on the line 3 3 of Fig. 1.

As shown in the drawing, I have associated my improved control device I with a uid compressing system for the purpose of illustration, the

`. iiuid compressing system further comprising a fluid compressor 2, a motor 3 for operating said compressor, and a, switch device 4 interposed in the circuit of said motor and controllable by said control device.

The control device I comprises a body 5, a iiexible diaphragm 6 mounted in said body, a follower ring 'l engaging said diaphragm and a hollow cover 8 having screw-threaded engagement with the body I and adapted to clamp said diaphragm between the body and follower ring.

A plurality of spaced lugs 9, I9, and II are provided in the top of the cover 8, and rotatably carried by a fulcrum pin I2, which is disposed in a bore through said lugs, are two bell crank levers,

" one of said bell crank levers having a substantially vertically disposed arm I3 and a substantially horizontally disposed arm I4, and the other of said bell crank levers having corresponding arms I5 and I6.

Carried by the lower end of the arm I3 is a roller I l, and carried by the lower end of the arm I4 is a roller I8. The rollers I1 and I8 are disposed on the opposite sides of the longitudinal center line of the control device and engage a follower disc or plate I9 loosely mounted within the follower ring I and engaging the diaphragm 8, the side of the follower plate engaged by said rollers being arranged in a plane at right angles to the axis of said follower plate.

The corresponding arms I4 and I6 of the two bell crank levers are oppositely disposed and engage a compression ring 20 through the medium or balls 2| and 22. An adjusting ring 23 having screw-threads 24 engaging corresponding screwthreads in the cover 8 provides a seat for one end of a compressible spring 25, the opposite end of said spring engaging the compression ring 29.

The adjusting ring 23 is provided at its periphery with spaced notches 26 which notches run transversely of the screw-threads 24 and are adapted to receive the pointed end 2l of a lock screw 28 having screw-threaded engagement with the cover 8. The outer transverse contour of the compression ring 29 is arcuate shaped in order to prevent locking engagement with the inside surface of the cover 8 in case said ring becomes twisted or cocked within the cover.

In order to obtain a mechanism which is sensi` tive in operation, the bell crank levers are provided with anti-friction bearings 29 and 30 at their fulcrum on pin I2 and anti-friction bearings 3l and 32 in the rollers I1 and I8.

Contained in the body 5 of the control device I are oppositely seating valves 33 and 34, the valve 33 having a stem 35 engaging the diaphragm 6. A spring 36 is provided in a chamber 31 for urging said valves to a position opposite to that shown in the drawing.

The switch device 4 comprises a casing containing a piston 38 adapted to shift a movable contact 39 out'of engagement with a pair of fixed contacts 49 and 4I, and a spring 42 for shifting said piston and movable contact 39 to the position shown in the drawing in which the movable contact 39 connects the contacts 49 and 4|.

In operation, the uid compressor 2 is adapted to compress iiuid `into a reservoir 43 through a pipe 44, the pipe 44 also connecting to a chamber 45 which communicates with a chamber 46 atvthe lower side of diaphragm 6, so that said diaphragm is subject to the pressure of iiuid in reservoir 43.,

When the pressure of fluid in reservoir 43 `and diaphragm chamber 46 is at atmospheric or below the operating pressure of the control device, the pressure of spring 25, which pressure is transmitted through the bell crank levers and follower plate I 9 to diaphragm 6 is suiiicient to maintain the diaphragm 6 in the cut-in position shown in the drawing in which the valve 33 is seated and the valve 34 is unseated.

With valve 34 unseated, the switch piston chamber 41 is connected with the atmosphere through pipe 48, chamber 49, past the unseated valve 34, through chamber 31 and atmospheric ports 56. Spring 42 is thereby permitted to hold the piston 38 and movable contact 39 in the position shown in the drawing, in which position a circuit is closed through the compressor motor 3 from a trolley wire 69 or other suitable source of electric current, by way of wire 5I, xed contact 4I, movable contact 39, fixed contact 48, wire 52 and ground 53. As a result, the compressormotor 3 operates compressor 2 to charge the reservoir 43 with fluid under pressure and consequently build up a iluid pressure chamber 46. This pressure in chamber 46 tends to deiiect diaphragm 6 upwardly and exerts a pressure through follower plate I9 upon the rollers I1 and I8, tending to move said rollers and the ends of the two bell crank lever arms I3 and I5 away from each other.

When the force thus applied to the end of the two bell crank lever arms I3 and I5 through the medium of the rollers I1 and I8 respectively, is suicient to overcome the opposing pressure of the spring 25 acting through said levers, the ends of the bell crank lever arms I3 and I5 are caused to move away from each other and the ends of the bell crank lever arms I4 and I6 are thereby operated to compress the spring 25.

In the operation just described, the force tend'- ing to move the roller I1 and the end of the bell crank lever arm I3 toward the right hand and away from the roller vI8 is equal to the product of one half of the pressure of diaphragm 6 on the follower plate I9 times the moment armof lever arm I3, which equals distance C from the the center of the roller I1 to a line passing through the center of the fullcrum pin I2 and at right angles to the diaphragm 6. Likewise, the force tending to move the roller I8 and the end of the bell crank lever arm I5 toward the left and away from the roller I1 is equal to the product of one half of the pressure of diaphragm 6 on the follower plate I9 times the moment arm of the lever arm I 5, which equals distance D. It is obvious that as the rollers I1 and I8 move away from each other the moment arms C and D. increase, thereby increasing the forces tending to move the rollers I1 and I8 apart. According to my invention, the rate of increasein the force tending to compress the spring 25 is greater than that of the opposing force of the spring as it is being compressed, with theresult that after the rollers do start to move apart, the rate of movement of the rollers increases and causes a sudden or sna'p Voperation of the mechanism to cut out position in which the deflection of the diaphragm 6 permits the spring 36 to shift valve 34 to its seat and to move valve 33 away from its seat. l

With-valve 33 unseated, Vfluid under pressure llows from reservoir 43 through diaphragm chamber 46,- chamber 49 and pipe 48- to the switch piston chamber 41. The pressure of fluid in chamber 41 shifts piston 38 upwardly, which moves the movable contact 39 out of engagement with the fixed `contacts 40 and 4I, thus opening the circuit through the compressor motor 3 and causingthe compressor to stop.

When the compressor is stopped, the use of fluid under pressure from the reservoir 43 reduces the pressure in said reservoir'and in dia# phragm chamber .46. which pressure acts through diaphragm 6 and Vfollower plate I9 on the rollers I1 and I8. When the pressure of fluid acting on the diaphragm 6 is reduced a predetermined amount, the pressure of spring 25 which opposes upward movement of diaphragm 6 causes the bell crank levers to operate to move the rollers I1 and I8 toward each other and deflect the diaphragm 6 downwardly to cut in position, as shown in the drawing. The movement of the rollers I1 and I8 toward each arm reduces the moment arms C and D and as a result reduces the force transmitted from the diaphragm 6 and follower I9 through the bell crank levers to spring 25 at a greater rate than the pressure of spring`25 reduces due to expansion, so that after the pressure of spring 25 starts K the rollers I1 and I8 moving toward each other,

sure isvented from the switch piston chamber 25 41 to the atmosphere through pipe 48, chamber 49, past valve 34 and through chamber 31 and the atmospheric ports 50. This permits spring 42 to shift the switch piston 38 downwardly and pull the movable contact 39 into engagement with the xed contacts 40 and 4I and thereby close the circuit through the compressor motor 3.v The compressor 2 is then again operated by the motor 3 to recharge the reservoir 43 with fluid under pressure, and when a predetermined pressure is thus obtained in'said reservoir and indiaphragm chamber 46, the control device is again operated as hereinbefore described to openy the compressor motor circuitso as to stop the compressor.

It will be noted that the operation of the control device I to open and close the circuit through the compressor motor 3 is governed by the adjusted pressure of spring 25, which is opposed by the reservoir pressure in diaphragm chamber 6. If it is desired to obtain a higher pressure in the reservoir 43 or toV have the control device `I open the motor circuit when a lower pressure is obtained in said reservoir, the adjustment or pressure of spring 25 may be changed so as to cause a different pressure in chamber 46 to operate the control valve to open the compressor motor circuit and stop the compressor in the same manner as hereinbefore described, and as a result, the compressor will then again be started when some proportionally diierent pressure is obtained in chamber 46, as governedby the rate of pressure change in the spring 25 upon expansion, as hereinbefore described. In order to adjust the spring 25 to limit the pressure in reservoir 43 to any desired degree, the lock screw 28 is removed from the cover portion 8. Any pointed tool, such as a screw driver, is then inserted through the opening from which the lock screw was removed and into one of the notches 26. Lateral pressure is then applied to the tool to turn the adjusting ring 23 in the direction desired for increasing or decreasing the adjusted pressure of spring 25.v When the desired adjustment of spring 25 is thus obtained, the tool is removed and the lock screw is replaced, the pointed end 21 of the lock screw entering one of the notches 26, soas to lock the adjusting ring in position.

In assembling the control device, the bellV crank levers are rst installed in position in the cover 8 and in order to insert the fulcrum pin I2, the cover is provided with an opening in each side disposed in line with the bore through the lugs S, i3, and il which receives the fulcrum pin I2, said openings being normally closed by screw plugs 5B and 5i. Through either one of these openings the fulcrum pin l2 is inserted into place, and in disassembling, the fulcrum pin I2 may be removed through one of these openings.

Avifnile one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A fluid pressure operated control device comprising a control member, a movable abutment subject on one side to variations in the pressure of fluid for controlling the operation of said member, the opposite side of said abutment being arranged in a plane at right angles to the direction of movement of said abutment, resilient means for controlling the movement of said abutment by the pressure of fluid, and a plurality of levers operatively engaging said opposite side of said abutment and providing a pressure trans-- mitting connection between said abutment and said resilient means, said levers having corresponding arms movable in diierent directions across one face of said abutment for amplifying the power delivered by said abutment to said resilient means upon an increase in the pressure of iiuid acting on said abutment and for amplifying the power delivered by said spring to said abutment upon a decrease in the pressure of uid acting on said abutment.

A fluid pressure operated control device comprising a control member, a movable abutment for controlling the operation of said member and subject on one side to variations in the pressure of uid, the opposite side of said abutment being disposed in a plane at right angles to the direction of movement of said abutment, a plurality of levers, rollers on corresponding arms of said levers slidably engaging the opposite side of said abutment for varying theleverage of said arms, and a spring for controlling the movement of said abutment, said spring acting on said levers for yieldingly opposing movement of said abutment by the pressure of fluid acting on said abutment.

3. A iluid pressure operated control device comprising a control member, a movable abutment subject on one side to variations in the pressure of iiuid for controlling the operation of said member, the opposite side of said abutment being disposed in a plane at right angles to the direction of movement of said abutment, a pair of bell crank levers having a pair of corresponding arms movable in opposite directions across said abutment for varying the leverage of said arms, a roller in each of said arms engaging said opposite side ci said abutment, and a spring for controlling the movement oi said abutment and acting on said levers for yieldingly opposing movement of said abutment by the pressure of uid acting on said abutment.

4. A fluid pressure operated control device comprising a control member, a movable abutment subject on one side to variations in the pressure of iuid for controlling the operation of said member, the'opposite side of said abutment being disposed in a plane at right angles to the direction of movement of said abutment, a plurality of levers having fulcrums arranged on a common axis, said levers slidably engaging said opposite r`5 side of said abutment and being movable therebyv in a direction-at substantially right angles to the direction of movement of said abutment, and' a spring acting through said levers for controlling the movement of said abutment by said variations in fluid pressure.

5. A fluid pressure operated control device comprising a casing containing a movable abutment subject to variations in uid pressure, a reciprocatory member operative in accordance with the operation of said abutment, a plurality of levers, a spring acting through said levers for opposing movement of said abutment, a seat for supporting said spring and adjustable in said casing for varying the initial compression of said spring, and locking means carried by said casing for maintaining said seat in its adjusted position.

6. A fluid pressure operated control device comprising a casing containing a movable abutment subject to variations in fluidpressure, a reciprocatory member operative in accordance with the operation of said abutment, a plurality of levers, a spring acting through said levers for opposing movement of said abutment, an adjustable spring seat for supporting said spring and having screwthreaded engagement in said casing, and a lockinU pin having screw-threaded engagement in said casing for locking said seat ring in its adjusted position.

'7. A fluid pressure operated control device comprising a casing provided with. a plurality of spaced lugs, a fulcrum pin carried by said lugs, a pair of levers mounted on said fulcrum pin, a movable abutment subject to variations in fluid pressure for operating said levers, a control member operated in accordance with the opera- 4tion of said abutment, a spring for opposing operation of said levers by said abutment, a ring carried by said spring and a ball interposed between said ring and each of said levers through 45 which the force of said spring is transmitted to oppose the operation of said levers by said abutment.

8. A uid pressure operated control device comprising a movable abutment subject to variations 50 in fluid pressure, a spring for controlling the movement of said abutment, said spring being adapted to oppose movement of said abutment in one direction upon an increase in fluid pressure and to move said abutment in the opposite di- 55 rection upon a decrease in fluid pressure, and a lever operatively connected to said spring and engaging one side of said abutment, the engaging point of which is shifted as the abutment moves the lever upon an increase in fluid pressure, for 60 increasing the power acting to compress said spring more rapidly than the power of said spring increases. f

9. A fluid pressure operated control device comprising a housing, a movable abutment mounted in said housing and subject on one side to variations in iluid pressure, a fulcrum pin carried by said housing, a pair of oppositely disposed like levers mounted on said pin and arranged diagonally with respect to the direction of movement of said abutment and slidably engaging said abutment, and resilient means surrounding said levers and interposed between the housing and said levers and acting on said levers in opposition to the pressure of fluid acting on said abutment l5 for controlling the movement of said abutment.

10. A iiuid pressure operated control device comprising a housing, a movable abutment mounted in said housing and subject on one side to variations in iiuid pressure, a fulerum pin carried by said housing, a pair of oppositely disposed bell crank levers carried by said pin, each of said bell crank levers having one arm arranged diagonally with respect to the direction of movement of said abutment and slidably engaging said abutment and having another arm extending outwardly, and a coil spring surrounding the first mentioned arm of said levers and carried bypsaid housing and acting on the last mentioned arm of said bell crank levers in opposition to the pressure of uid on said abutment.

11. A fluid pressure operated control device comprising a housing, a movable abutment mounted in said housing and subject on one side to variations in fluid pressure, a fulcrum pin carried by said housing, a pair of oppositely disposed bell crank levers carried by said pin, each of said bell crank levers having one arm slidably engaging said abutment at an angle to the direction of movement of said abutment and having another arm extending outwardly, a spring sea-t adjustably mounted interiorly of said housing, and a coil spring surrounding the first mentioned arm of the bell crank levers and interposed between said spring seat and the second mentioned arm of the bell crank levers for exerting a pressure on said abutment in opposition to the pressure of fluid acting on said abutment.

12. A uid pressure operated control device comprising a control member, a movable dlsc sub- 1 5 ject on one face to variations in the pressure of fluid for controlling the operation of said member, a plurality of levers slidably engaging the opposite face of said disc for varying the lever rotating component of the force transmitted from 10 the disc to the levers, and resilient means acting on said levers and yieldingly resisting movement of said levers by said disc for opposing movement of said disc by iiuid pressure.

13. A fluid pressure operated control device 15 comprising a movable abutment subject on one side to variations in uid pressure, a spring for controlling the movement of said abutment and acting on said abutment in opposition to said fluid pressure, and a lever interposed between 20 and engaging said movable abutment and spring and operative upon an increase in uid pressure on said abutment to increase the moment of the fluid pressure applied force more rapidly than the moment of the spring force increases, and 25 operative upon a reduction in uid pressure on said abutment to decrease the moment of the iiuidpressure applied force more rapidly than vthe moment of the spring force decreases.

BENJAMIN H. THOMPSON. 30 

